/Engine/Source/Editor/UnrealEd/Public/Kismet2/BlueprintEditorUtils.h
Gets AssetData for all child classes of a given blueprint
Number of child blueprints found
static int32 GetChildrenOfBlueprint ( [UBlueprint](API\Runtime\Engine\Engine\UBlueprint) * InBlueprint, [TArray](API\Runtime\Core\Containers\TArray)< [FAssetData](API\Runtime\CoreUObject\AssetRegistry\FAssetData) > & OutChildren, bool bInRecursive )